The invention relates to a protective surgical drape construction for an operation microscope wherein an optically clear protective window is provided for the objective lens of the microscope.
Objective-lens protection has been a feature of protective surgical drapes for operation microscopes. Generally, such constructions take the form of a flanged annular body wherein the flange is sealed to the border of a local circular opening in the drape material and wherein the annular body is adapted for telescoping removable attachment to the objective-lens barrel or mount of the microscope. The annular body is axially short and provides mounting for a flat lens-protecting optically transparent element, which may be of glass or a suitable plastic, mounted perpendicular to the optical axis of the objective. Modern surgical microscopes of the character indicated incorporate sophisticated mountings with six dimensions of manipulated orientation of the objective, namely, three orthogonal axes of rotatable adjustment, and three orthogonal axes of rectilineal displacement, and for certain situations of adjusted orientation in relation to relatively fixed illumination, internal reflection between the objective lens and the flat protective transparent element can be a source of degraded viewing through the microscope.